An electrical system (an integrated circuit, a computer system or a microcontroller, as examples) may contain both digital and analog subsystems. The digital subsystem may contain, as examples, a clock generator, bus interfaces (a Universal Serial Bus (USB) interface and a serial peripheral interface (SPI) interface, as examples), a serial communication interface (a universal asynchronous receiver/transmitter (UART) interface, for example), programmable timers, and so forth. The analog subsystem may include such components as an analog-to-digital converter (ADC), current drivers, voltage level translators and so forth.
As a more specific example, an integrated circuit (IC) may contain digital and analog subsystems that are accessed via the pads of the IC. The voltage of a pad of the IC may, for a given application, be higher than the supply voltage of the IC.